Divergence ratio distance mapping camera

ABSTRACT

The present invention relates to a method and system for detecting and mapping three-dimensional information pertaining to one or more target objects. More particularly, the invention consists of selecting one or more target objects, illuminating the one or more target objects using a first light source and capturing an image of the one or more target objects, then, illuminating the same one or more target objects using a second light source and capturing an image of the one or more target objects and lastly calculating the distance at the midpoint between the two light sources and the one or more target objects based on the decay of intensities of light over distance by analyzing the ratio of the image intensities on a pixel by pixel basis.

This application claims the benefit of U.S. patent application Ser. No.11/690,503, filed Mar. 23, 2007.

FIELD OF THE INVENTION

The present invention relates to a method and system for detecting andmapping three-dimensional information pertaining to an object. Inparticular, the invention relates to a method and system that makes useof the divergence of light over distance as a means of determiningdistance.

BACKGROUND OF THE INVENTION

Distance mapping or depth mapping cameras have become ubiquitous innumerous fields such as robotics, machine vision for acquiringthree-dimensional (3D) information about objects, intelligent transportsystems for assisting driver safety and navigation, bioscience fordetecting 3D laparoscopic images of internal organs, non-contactfingerprinting, and image manipulation in movie or television studios.

To achieve the goal of distance mapping an object in order to acquireits 3D information, numerous methods have been developed. Thetriangulation method uses two or more images taken by strategicallyplaced cameras to calculate the position of the target object. The 3Dinformation is obtained by synchronizing the movement of the lightprojection spot with the direction of the return path of the lightscattered to the detector. This triangulation method is limited in thatit is too slow and generally can not provide for the real-time operationof a television camera.

The time of flight method makes use of the time required for a roundtrip of a laser beam using a phase or frequency modulated probe light. Aheterodyne detection converts the phase or frequency information intothe distance to the target object. While depth resolution can be withinmicrometers, time of flight methods can be limited to the order ofminutes in providing a depth map of a target object.

Projection methods determine depth information from the patterns ofconfigured light projected onto a target object. The best knownprojection method is the moiré technique. The moiré techniqueincorporates two grid patterns projected before and after the surfacedistortion to generate a moiré pattern of the deformed surface. While amoiré pattern can be readily generated, not so are the correspondingdistance calculations. This distance is calculated in a manner similarto applying triangulation at every intersection of the pattern.

The AXI-VISION CAMERA™ method as described in U.S. Pat. No. 7,0165,519B1 is based on a hybrid of the projection and time of flight methods.The projecting light is temporally rather than spatially modulated. Toacquire the depth pattern, an instantaneous time of flight pattern iscaptured using an ultra-fast shutter. Distance is then calculated atevery pixel providing a picture quality to that of High DefinitionTelevision (HDTV). To achieve its results, the AXI-VISION CAMERA™ methodrequires a large number of fast response time LEDs, a photomultiplierbased shutter that are all secured to the AXI-VISION CAMERA™.

The object of the present invention is to provide a method and devicefor detecting and mapping three-dimensional information pertaining toone or more target objects while further addressing the limitations ofthe prior art.

SUMMARY OF THE INVENTION

A method of obtaining three-dimensional information for one or moretarget objects is provided, characterized in that it comprises the stepsof: (a) selecting one or more target objects; (b) illuminating the oneor more target objects using a first light source at a distance X₁ fromthe one or more target objects, and capturing an image I₁ of the one ormore target objects using at least one camera device; (c) illuminatingthe one or more target objects using a second light source at a distanceX₂ from the one or more target objects, and capturing an image I₂ of theone or more target objects using the at least one camera device; and (d)calculating the distance X between the first and second light sources,and the one or more target objects, based on the decay of intensities oflight sources over distances X₁ and X₂, using the ratio of the imageintensities between the images I₁ and I₂.

In another aspect of the invention a system for obtainingthree-dimensional information for one or more target objects is providedcharacterized in that it comprises: (a) at least two light sources,including a first light source at a distance X₁ from one or more targetobjects, and a second light source at a distance X₂ from the one or moretarget objects; and (b) at least one camera device linked to, orincorporating, at least one computer device, the camera device, or thecamera device and computer device together, being operable to: (i)capture and store digital frame information, including capturing animage I₁ of the one or more target objects, illuminated by the firstlight source, and an image I₂ of the same one or more target objects,illuminated by the second light source; and (ii) calculate the distanceX between the at least two light sources and the one or more targetobjects based on the ratio of the decay of image intensities of lightsources over distances X₁ and X₂ using the ratio of the imageintensities between the images I₁ and I₂.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of the preferred embodiment(s) is(are) providedherein below by way of example only and with reference to the followingdrawings, in which:

FIG. 1 a illustrates the distance mapping apparatus capturing an imageI₁ of a target object using the first illuminating device as a lightsource.

FIG. 1 b illustrates the distance mapping apparatus capturing an imageI₂ of a target object using the second illuminating device as a lightsource.

FIG. 1 c illustrates the amplitude ratio between I₁ and I₂.

FIG. 2 further illustrates the geometry of the divergence ratio distancemapping camera.

FIG. 3 is a graph that illustrates the relationship between amplituderatio R and the distance r/d.

FIG. 4 illustrates the ability to move the divergence ratio distancemapping camera to an arbitrary location.

FIG. 5 illustrates the double illuminator sets for eliminating shadows.

FIG. 6 illustrates a more detailed apparatus for the divergence ratiodistance mapping camera.

FIG. 7 a image taken with front illumination.

FIG. 7 b image taken with back illumination.

FIG. 7 c photograph of the object

FIG. 7 d measured depth profile of the object.

In the drawings, preferred embodiments of the invention are illustratedby way of example. It is to be expressly understood that the descriptionand drawings are only for the purpose of illustration and as an aid tounderstanding, and are not intended as a definition of the limits of theinvention. It will be appreciated by those skilled in the art that othervariations of the preferred embodiment may also be practised withoutdeparting from the scope of the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 a illustrates the distance mapping apparatus 1 capturing an imageI₁ of a target object 3 using a first illuminating device 5 as a lightsource. The first illuminating device 5 illuminates the target object 3and the camera device 7 captures an image I₁ that is stored by thesystem on a storage medium (see FIG. 6).

FIG. 1 b illustrates the distance mapping apparatus 1 capturing an imageI₂ of a target object 3 using a second illuminating device 9 as a lightsource. The second illuminating device 9 illuminates the target object 3and the camera device 7 captures an image I₂ that is stored by thesystem on a storage medium (see FIG. 6).

FIG. 1 c illustrates the amplitude ratio between I₁ and I₂. As furtherexplained (see FIG. 2), through the derivation of the equation tocalculate distance, the present invention functions by comparing therelative image intensities between I₁ and I₂ on a pixel by pixel basis.FIG. 1 c demonstrates a graph wherein the relative image intensitiesbetween I₁ and I₂ have been plotted providing the amplitude ratio.

FIG. 2 further illustrates the geometry of a divergence ratio distancemapping camera apparatus, in accordance with one aspect of the presentinvention. The apparatus is set up in the following manner: a cameradevice 7 is at a distance r from the target object 3, a firstilluminating device 5 labelled LED s₁ is at a distance X₁ (r−d) from thetarget object 3, and a second illuminating device 9 labelled LED s₂ isat a distance X₂ (r+d) from the target object 3. The camera device 7 isalso linked to, or incorporates, a computer device, such as a processor11 which is operable to compute the distance to the target object 3 fromthe relative image intensities of I₁ and I₂. As mentioned, the cameradevice 7 firstly captures an image I₁ of the target object 3 using thefirst illuminating device 5 LED s₁ as a light source. This image I₁ isstored by a storage medium, such as a frame grabber 21 (see FIG. 6) ofprocessor 11 (the frame grabber 21 being hardwired to processor 11 orincorporated into computer programming made accessible to processor 11).The camera device 7 then captures an image I₂ of the target object 3using the second illuminating device 9 LED s₂ as a light source. Thisimage I₂ is also stored by the storage medium, such as the frame grabber21 of the processor 11.

In order to calculate the distance to the target object 3, the processor11 is operable to compare the relative image intensities of I₁ and I₂ ona pixel by pixel basis. Before this comparison can be performed, theprocessor 11 calculates the image intensity of I₁ using the firstilluminating device 5 LED s₁ as a light source as well as calculatingthe image intensity of I₂ using the second illuminating device 9 LED s₂as a light source. The calculated pixel distance information is storedto the storage medium.

The image intensity calculation is further utilized to calculate adistance X between the first and second light sources. In one embodimentof the present invention, X is calculated based on the distance betweenthe one or more target objects and the midpoint of the first and secondlight sources. In another embodiment of the present invention, X may bespecifically calculated based on the decay of light intensity overdistances X₁ and X₂, using the ratio of the image intensities betweenthe images I₁ and I₂. The decay of light intensity over distance X is1/x^(n), where n can be either a positive or negative real numberincluding a non-integer.

In one embodiment of the present invention, the first image I₁ and thesecond image I₂ are stored on a storage medium known by individualsskilled in the art; the distance X at the midpoint between the two lightsources and the one or more target objects is calculated by analyzingimages I₁ and I₂ on a pixel by pixel basis; the calculated pixeldistance information is stored using a known coordinate storage medium.

In one embodiment of the present invention, the pair of light sources 5,9 that are used are infra red point light sources. It is commonly knownto those skilled in the art that intensity of a point light sourcedecays with the square of the distance due to the divergence property oflight. Therefore the intensity of the light from the illuminating device5 LED s₁ directed at the target object 3 located at a distance r fromthe camera device 7 is:

$\begin{matrix}{I_{in} = \frac{P_{0}}{4{\pi\left( {r - d} \right)}^{2}}} & (1)\end{matrix}$where P₀ is the power of the point source from first light source 5 LEDs₁. In addition, the target object 3 reflects light back towards thecamera device 7. The amount of the reflection is characterized by theradar term of back scattering cross section σ. The light powerassociated with the back scattering toward the camera device 7 is:

$\begin{matrix}{P_{sc} = \frac{\sigma\; P_{0}}{4{\pi\left( {r - d} \right)}^{2}}} & (2)\end{matrix}$

Since the reflected light that is propagating back to the camera device7 also obeys the divergence property, the intensity of the reflectedlight decays with the square of the distance resulting in the followinglight intensity equation for I₁:

$\begin{matrix}{I_{1} = \frac{\sigma\; P_{0}}{\left\lbrack {4{\pi\left( {r - d} \right)}} \right\rbrack^{2}r^{2}}} & (3)\end{matrix}$

In a similar manner the light intensity equation for the image I₂ of thetarget object 3 using the second illuminating device 9 LED s₂ as a lightsource is derived, by simply replacing r−d by r+d in Eq. (3) in thefollowing manner:

$\begin{matrix}{I_{2} = \frac{\sigma\; P_{0}}{\left\lbrack {4{\pi\left( {r + d} \right)}} \right\rbrack^{2}r^{2}}} & (4)\end{matrix}$

As one can clearly see, Eqs. (3) and (4) share a number of commonfactors and by importing these two equations in the amplitude ratio Requation:

$\begin{matrix}{R = \sqrt{\left( {I_{1}/I_{2}} \right)}} & (5)\end{matrix}$

Results in the following reduced equation for amplitude ratio R:R=(r+d)/(r−d)  (6)

Rearranging Eq. (6) to solve for the value of interest r, that being thedistance between the camera device 7 and the target object 3 results inthe following equation:r=d(R+1)/(R−1)  (7)

Of special note, such factors as the back scattering cross section σ ofthe target object 3, point source light power P₀ (assuming that bothpoint sources: first light source 5 LED s₁ and second light source 9 LEDs₂ have equivalent power), and the divergence r⁻² of the return lightreflected from the target object 3 towards the camera device 7 all ofwhich appear in both Eqs. (3), and (4) are cancelled out from thecalculation and accurate distance is measured regardless of the targetobject colour and texture.

Using the derived equation for distance Eq. (7), the processor 11, thendetermines the distance of each pixel on a pixel by pixel basis and isoperable to store the information in a coordinate storage medium as adistance map for the target object 3 in a manner that is known to thoseskilled in the art. This distance map for the target object 3, containsall of the pixel positional information of the target object 3.

FIG. 3 is a plot that illustrates the relationship between amplituderatio R and the distance r/d. The sensitivity of the measurement isoptimum near the origin and reduces as the asymptote is approached. Itis also interesting to note that the Eq. (7) can be rewritten in thefollowing manner:

$\begin{matrix}{{\left( {\frac{x}{d} - 1} \right)\left( {R - 1} \right)} = 2} & (8)\end{matrix}$and the exchange of coordinates between x/d and R gives the same curveshape. As shown by FIG. 3, the curve is symmetric with respect to a 45degree line, and there is the same asymptote of unity in both the R andthe r/d axes.

FIG. 4 illustrates the ability to move the divergence ratio distancemapping camera or camera device 7 to an arbitrary location. For ease ofequation derivation, the ratio distance mapping camera apparatus waspreviously described with the camera device 7 in-line with the twoilluminating devices: first light source 5 LED s₁ and second lightsource 9 LED s₂. As indicated by FIG. 4 and as will be demonstrated bythe following equation derivation, the camera device 7 may be placed inan arbitrary location and the actual distance that is being measured isbetween the target object 3 and the center of the two illuminatingdevices (first light source 5 LED s₁ and second light source 9 LED s₂).As depicted in FIG. 4, the position of the camera device 7 has beenrelocated from the center of the two illuminating devices (first lightsource 5 LED s₁ and second light source 9 LED s₂) to an arbitrarylocation (x₁,z₁) in the x-z plane. Taking the origin (0,0) of thiscoordinate system to be the center of the light point sources, thetarget object 3 is located along the z-axis at coordinate (0,z). Theseparation between the two light point sources (first light source 5 LEDs₁ and second light source 9 LED s₂) is kept constant at 2d as before.

Incorporating this information from the new coordinate system into Eqs.(3) and (4) results in the following equations:

$\begin{matrix}{I_{1} = \frac{\sigma\; P_{0}}{\left\lbrack {4{\pi\left( {z - d} \right)}} \right\rbrack^{2}\left\lbrack {\left( {x - x_{1}} \right)^{2} + z_{1}^{2}} \right\rbrack}} & (9) \\{I_{2} = \frac{\sigma\; P_{0}}{\left\lbrack {4{\pi\left( {z + d} \right)}} \right\rbrack^{2}\left\lbrack {\left( {x - x_{1}} \right)^{2} + z_{1}^{2}} \right\rbrack}} & (10)\end{matrix}$

Solving for the amplitude ratio R using Eqs. (9) and (10) results in thefollowing equation:r=d(R+1)/(R−1)  (11)which is identical to the previously derived Eq. (7).

It is interesting to note that the distance measured is always alongthis z axis between target object 3 and the center of the twoilluminating devices (first light source 5 LED s₁ and second lightsource 9 LED s₂). This ability to position the camera independent of theorientation of the light sources provides considerable operationaladvantage that could be readily incorporated into different embodimentsand arrangements of the present invention. For example if the LED's areinstalled either on the studio ceiling or wall, the hand-held cameradoes not have to bear an additional weight or attachment.

It should be noted that as a caveat, it is discouraged that the camerastray too far off the connecting line between the two points sourcesbecause shadows may be created in the mapped image. A countermeasure toassist in reducing shadows in the mapped image is described below (FIG.5).

FIG. 5 illustrates the double illuminator sets for eliminating shadows.As previously described, if the camera device 7 is positioned too awayfar from the connecting line between the two point sources of light(first light source 5 LED s₁ and second light source 9 LED s₂), shadowsmay be incorporated into the distance map. The shadow is an undesirableimage product and may corrupt the accuracy of the distance map. In orderto minimize the effect of shadowing, FIG. 5 demonstrates an embodimentof the present invention wherein two sets of LEDs are used (illuminatorset 1 13 at a distance of X₁ and X₃ from the target object andilluminator set 2 15 at a distance of X₂ and X₄ from the target object)to illuminate the target object 3, in this case an overturned cup. Asemphasized by the shape of the overturned cup target object 3, each pairof illuminator sets 13, 15 cast their own specific shadow (see shadow ofset 1 17 and shadow of set 2 19). By incorporating two pairs ofilluminator sets 13, 15, the pair of shadows 17, 19 can be reduced andthe corresponding distance map of the overturned cup target object 3improved. All of the light sources applied may be of the same type.

FIG. 5 further demonstrates an embodiment of the invention permittingthe capture of additional images, corresponding to the additional lightsources. By illuminating the one or more target objects using a thirdlight source at a distance X₃ from the one or more target objects it ispossible to capture an image I₃ of the one or more target objects. Andby illuminating the one or more target objects using a fourth lightsource at a distance X₄ from the one or more target objects it ispossible to capture an image I₄ of the one or more target objects. Acalculation of the set of distances X′2 between the third and fourthlight sources and the one or more target objects based on the decay ofintensities of light sources over distances X₃ and X₄ may be performedusing the ratio of the image intensities between the images I₃ and I₄ ona pixel by pixel basis. At this point it is possible to merge the set ofdistances developed by the set of distances X′1 between the first andsecond light sources with the set of distances developed by the secondset of distances X′2, thereby minimizing the effect of light sourceshadowing.

Thus, the final distance map for the overturned cup target object 3 isactually comprised of a merging of the distance map developed by thefirst illuminator set 13 with the distance map developed by the secondilluminator set 15. In the processor 11 of the frame grabber 21, the twoderived distance maps are compared on a pixel by pixel basis and anappropriate pixel is selected by comparison. The comparison is madepossible due to the fact that the relative position of the camera device7 and the target object 3 has not been changed as between the twodistance maps and a simple merging step common to individuals skilled inthe art is sufficient to combine the two distance maps to form a finaldistance map. This final distance map generally minimizes the effect ofshadows on the pixel positioning to provide a more exact result.

FIG. 6 illustrates a more detailed apparatus for the divergence ratiodistance mapping camera. The more detailed apparatus is comprised of thecamera device 7 connected to a computer device including a frame grabber21 (part of the processing unit 11), also connected to a video syncseparator 23 which in turn is connected to a video microcontroller 25that controls the front 27 and back 29 LED drivers that control the pairof illuminating devices i.e. the front light source 5 LED s₁ and backlight source 9 LED s₂. In addition, the video microcontroller 25 may beconnected to a monitor display 31 or some other medium to display thedistance map that it calculates.

In one embodiment of the present invention, a distance mapping system isprovided including: one or more target objects; at least one cameradevice and at least two light sources. The at least one computer deviceis linked to the camera that is operable to capture digital frameinformation, and calculate distance X between the center of the lightsources and one or more target objects based on the method of thepresent invention.

In the preferred embodiment of the present invention, the compositevideo signal out of an infra red camera device 7 was used to synchronizethe timing of the front and back infra red illuminating devices 5, 9.The composite video signal is fed into a video sync separator 23 thatextracts the vertical sync pulse and also provides the odd/even fieldinformation. This output from the sync is provided to the videomicrocontroller 25.

The video microcontroller 25 is operable to signal the front LED 5 toilluminate when the camera device 7 is in the even field and an image I₁is captured and stored in the frame grabber 21 (see FIG. 7 a). The videomicrocontroller 25 is operable to signal the back LED 9 to illuminatewhen the camera device 7 is in the odd field and an image I₂ is capturedand stored in the frame grabber 21 (see FIG. 7 b). In this manner thevideo microcontroller is operable to signal the first light source andthe second light source to illuminate the one or more target objects ina sequential manner. Additionally, the video microcontroller and thecamera device are linked to enable the camera device to capture theimages of the one or more target objects sequentially, while illuminatedby the first and second light sources in sequence. The frame grabber 21then applies the derived distance Eq. (7) to the two images I₁ and I₂ ona pixel by pixel basis and the distance map of the target object 3 canbe displayed on a monitor display (31) (see FIG. 7 d).

In one embodiment, the depth of an image or the distance map can bedisplayed using a colour code with red being the shortest distance andpurple being the longest distance. This same information can bedisplayed using black and white wherein dark represents the shortestdistance and white represents the longest distance.

FIG. 7 a illustrates an image taken with front illumination. This is animage of a face of a statue taken by an IR camera device 7 only usingfront illumination 5 and stored in the frame grabber 21.

FIG. 7 b illustrates an image taken with back illumination. This is animage of a face of a statue taken by an IR camera device 7 only usingback illumination 9 and stored in the frame grabber 21.

FIG. 7 c illustrates a photograph of the object. This is a normalphotograph of the face of the statue for comparison with the generateddepth profile (see FIG. 7 d).

FIG. 7 d illustrates a measured depth profile of the object. This is theresult of the frame grabber applying the distance Eq. (7) on the imagetaken in FIG. 7 a and the image taken in FIG. 7 b on a pixel by pixelbasis. As previously explained, dark represents the shortest distancebetween the target object 3 and the midpoint between the front 5 andback 9 LED devices while white depicts longer distances between thetarget object 3 and the midpoint between the front 5 and back 9 LEDdevices.

It should be noted that there exist practical limits on the range of thecamera of the present invention. The measurement depends upon thedivergence of light. This limit may be extended by unbalancing theintensities of these two illuminating light sources by avoiding thesaturation of the CCD camera device 7 when the front LED 5 is too closeto the target object 3. In particular when the distance z to the targetobject 3, is large as compared to the LED separation distance 2d, thelight intensities Int_(A), and Int_(B) are more or less the same but asthe distance to the target object 3 become excessively short and thefront light 5 intensity Int_(A) becomes much larger than Int_(B), thisdifference between the light intensities no longer remains within thelinear range of the CCD camera device 7. As mentioned this limit may beextended by either reducing the exposure time of the CCD camera device 7when capturing the image with the front LED or by reducing the outputpower of only the front LED 5 by a known factor N and keeping Int_(B)unchanged. An appropriate value for N may be found by monitoring thecomposite video signal of the CCD camera device 7.

In a particular aspect of the invention, the distance mapping system isoperable to provide the three-dimensional information and beincorporated, for example, into the automobile industry. The system maybe integrated with an automobile distance mapping system or accidentprevention system. The distance mapping apparatus of the presentinvention could be incorporated to quickly provide for the exact 3Dpixel positional information for prototype vehicles. The distancemapping device provides for real time operational advantages. Most othermethods need time for setting up the sensors at specified locations evenbefore making a measurement. The distance mapping apparatus is ahand-held operation that can aim at target at any angle and locationrelative to the object. Additional embodiments of the invention may befurther incorporated into aspects of the automobile industry.

In another particular aspect of the invention, the distance mappingsystem is linked to an on-board computer system of a vehicle and isoperable to provide environmental 3D information to assist the on-boardsystem of the vehicle in accident prevention. The distance mappingsystem can differentiate the radar echo from the trees on the pavementfrom that of an oncoming moving car from the shape of the objects.Generally, ordinary radar systems do not function in this manner. Forexample, when a car equipped with an ordinary radar system negotiatesthe curve of a road the ordinary radar system may mistake trees alongthe side of the road as an oncoming car and the automatic braking systemwould be triggered. In other words, an ordinary radar system functionsoptimally when the equipped car is travelling along a straight road butnot along a curved road.

In another aspect of the invention, the distance mapping system could beincorporated into traffic surveillance system and is operable to obtainthree-dimensional information associated with automobiles, suchthree-dimensional information providing a basis for establishing makeand model information for automobiles. For example, in this manner thepresent invention may be used to assist in determining the make andmodel of a vehicle by only calculating the distance map of one profile.The detailed information of the one profile of the vehicle could beextrapolated to recreate a 3D representation of the vehicle, or it couldbe used to compare with stored library information of 3D representationsof vehicles for greater accuracy and identification.

In another particular aspect of the invention, a distance mapping systemis provided as previously described wherein the distance mapping systemis operable to provide distance information relative to one or moretarget objects to an individual with a visual impairment regarding theirphysical environment. For example, environmental three-dimensionalinformation may be provided so as to assist an individual who isvisually impaired. Due to the ability to freely position the cameradevice 7, the distance mapping system could be readily incorporated intoan assistive cane or incorporated into the outer apparel of a visuallyimpaired individual. The distance mapping system could then providesignals regarding the calculated environmental information to theindividual based upon predefined criteria such as the size and the shapeof an object. Ordinary echo based warning systems are not capable ofdiscerning whether an object is a man, a tree, or a building. Inaddition, the distance mapping system could be readily incorporated intoa humanoid robotic system to provide omni directional eye vision to morequickly identify its surroundings and avoid obstacles. Alternatively,the system of the present invention may be integrated with any type ofrobot to provide distance mapping information to the robot in relationto one or more target objects.

In yet another particular aspect of the invention, the distance mappingsystem is operable to provide environmental 3D information for a 3Dvirtual studio. Due to the ability to freely position the camera device7, a 3D virtual studio could be readily set up wherein the live sceneryis inserted either in the foreground or background of a computergenerated graphic, but could be positioned anywhere within the frame aslong as the computer generated graphics itself as the distanceinformation in each pixel. In addition, the 3D virtual studio couldfunction in real time and could greatly assist television broadcasts.For this purpose the system of the present invention may be integratedwith a television studio system to provide three-dimensional informationthat enables editing of one or more target objects in athree-dimensional studio environment. All too often live reporters aredisrupted by individuals walking into the video frame; these individualscould be removed in real time by distance discrimination. The real timeediting need not be limited to the removal of individuals, once the 3Dinformation has been obtained for a video frame, virtually anything maybe edited into and out of the video feed.

In a still other aspect of the present invention, the distance mappingsystem is incorporated into the cosmetic industry to quickly provide a3D imaging of a patient without having to manufacture a moulding. Morespecifically, this 3D imaging could be used to assist a plastic surgeonand subsequently the patient in determining how certain features mayappear after a procedure. In addition, the 3D imaging information couldbe used by an orthodontist who makes teeth mouldings, the providedinformation could greatly reduce the need of an uncomfortable mouldingprocess. The current distance mapping system would allow for a 3D imageto be made without any contact with the patient and a non-invasivemanner.

In another aspect of the present invention, the distance mapping systemmay be readily incorporated into a security system and more specificallylinked to a fingerprint capture system, wherein the distance mappingsystem is accomplished in a touch-less non contact method that providesa three-dimensional creation of a 3D map of a fingerprint without havingto ink the individual's fingers or touch a panel for scanning of thepalm. In another security implementation of the present invention, thedistance mapping system may be readily incorporated into surveillancesystems to provide for profile information on an individual. If a frontprofile of an individual has been captured, the distance mapping systemcould be used to generate a side profile of the individual.Additionally, if the side profile of an individual has been captured,the front profile could be extrapolated based upon the 3D distancemapping information.

In yet another aspect of the present invention, the system may beintegrated with a biometric authentication system to enablebio-authentication of individuals based on touch-less capture ofbio-authentication information such as fingerprints.

In another aspect of the present invention, a distance mapping system isprovided wherein the distance mapping apparatus may substitute orreplace the illuminating light sources with sound transducers to achievea sonar distance mapping camera for underwater objects like a submarineor a school of fish result.

In yet another embodiment of the present invention, a distance mappingsystem is provided wherein for the purposes of real time 3D informationgathering, the sources are of the same type (i.e. acoustic sources orlight sources).

What is claimed is:
 1. A method of obtaining three-dimensionalinformation for one or more target objects is provided comprising: (a)selecting one or more target objects; (b) illuminating the one or moretarget objects using a first illuminating device at a distance X₁ fromthe one or more target objects, and capturing an image I₁ of the one ormore target objects using at least one camera device; (c) illuminatingthe one or more target objects using a second illuminating device at adistance X₂ from the one or more target objects, and capturing an imageI₂ of the one or more target objects using the at least one cameradevice; and (d) calculating the set of distances X′1 between the firstand second illuminating devices, and the one or more target objects,based on the decay of intensities of the first and second illuminatingdevices over distances X₁ and X₂, using the ratio of the imageintensities between the images I₁ and I₂, (e) illuminating the one ormore target objects using a third illuminating device at a distance X₃from the one or more target objects and capturing an image I₃ of the oneor more target objects; (f) illuminating the one or more target objectsusing a fourth illuminating device at a distance X₄ from the one or moretarget objects and capturing an image I₄ of the one or more targetobjects; (g) calculating the set of distances X′2 between the third andfourth illuminating devices and the one or more target objects based onthe decay of intensities of illuminating devices over distances X₃ andX₄ using the ratio of the image intensities between the images I₃ andI₄; (h) merging the set of distances developed by the set of distancesX′1 between the first and second illuminating devices with the set ofdistances developed by the second set of distances X′2, therebyminimizing the effect of illuminating device shadowing; and wherein thedecay of the illumination intensity over distance X is 1/x^(n), where ncan be any positive or negative real number including a non-integer. 2.The method for obtaining three-dimensional information for one or moretarget objects as defined in claim 1, wherein the distance X between thetwo illuminating devices the one or more target objects is calculatedbased on the distance between the midpoint of the two illuminatingdevices and the one or more target objects.
 3. The method for obtainingthree-dimensional information for one or more target objects as definedin claim 1, wherein: (a) the first image I₁ and the second image I₂ arestored on a known storage medium; (b) the distance between the one ormore target objects and the midpoint between the two illuminatingdevices is calculated by analyzing images I₁ and I₂ on a pixel by pixelbasis; and (c) the calculated pixel distance information is stored usinga known coordinate storage medium.
 4. The method for obtainingthree-dimensional information for one or more target objects as definedin claim 1, comprising the further step of illuminating the one or moretarget objects with additional illuminating device for reduction of theimpact of shadow on the measurement of illumination intensity.
 5. Asystem for obtaining three-dimensional information for one or moretarget objects comprising: (a) at least two illuminating devices,including a first illuminating device at a distance X₁ from one or moretarget objects, and a second illuminating device at a distance X₂ fromthe one or more target objects; and (b) at least one camera devicelinked to, or incorporating, at least one computer device, the cameradevice, or the camera device and computer device together, beingoperable to: (i) capture and store digital frame information, includingcapturing an image I₁ of the one or more target objects, illuminated bythe first illuminating device, and an image I₂ of the same one or moretarget objects, illuminated by the second illuminating device; (ii)calculate the set of distances X′1 between the at least two illuminatingdevices and the one or more target objects based on the ratio of thedecay of image intensities of illuminating devices over distances X₁ andX₂ using the ratio of the image intensities between the images I₁ andI₂; (iii) capture an image I₃ of the one or more target objects using athird illuminating device at a distance X₃ from the one or more targetobjects; (iv) capture an image I₄ of the one or more target objectsusing a fourth illuminating device at a distance X₄ from the one or moretarget objects and capturing; (v) calculate a set of distances X′2between the third and fourth illuminating devices and the one or moretarget object based on the decay of intensities of illuminating devicesover distances X₃ and X₄ using the ratio of the image intensitiesbetween the images I₃ and I₄; (vi) merge the set of distances X′1between the first and second illuminating devices with the set ofdistances developed by the set of distances X′2, thereby minimizing theeffect of illuminating device shadowing; and wherein the decay of theillumination intensity over distance X is 1/x^(n), where n can be anypositive or negative real number including a non-integer.
 6. The systemfor obtaining three-dimensional information for one or more targetobjects as defined in claim 5, wherein the illuminating devices are ofthe same type.
 7. The system for obtaining three-dimensional informationfor one or more target objects as defined in claim 5, wherein tominimize the effect of illuminating device shadowing the system furthercomprises: (a) an additional set of illuminating devices of the sametype.
 8. The system for obtaining three-dimensional information for oneor more target objects as defined in claim 5, wherein the distance Xbetween the first and second two illuminating devices and the one ormore target objects is calculated based on the distance between the oneor more target objects and the midpoint of the first and secondilluminating devices.
 9. The system for obtaining three-dimensionalinformation for one or more target objects as defined in claim 5,wherein the system is linked to a storage medium, and characterized inthat the computer device is operable to: (a) store the first image I₁and the second image I₂ to the storage medium; (b) calculate thedistance between the one or more target objects and the two lightilluminating devices by analyzing images and I₂ on a pixel by pixelbasis; and (c) store the calculated pixel distance information to thestorage medium.
 10. The system for obtaining three-dimensionalinformation for one or more target objects as defined in claim 9,wherein the system is operable to generate a distance map for the one ormore target objects based on the calculated pixel distance information.11. The system for obtaining three-dimensional information for one ormore target objects as defined in claim 5, wherein the camera device islinked to at least one video microcontroller for controlling theilluminating devices.
 12. The system for obtaining three-dimensionalinformation for one or more target objects as defined in claim 5,wherein the video microcontroller is linked to the illuminating devices,and is operable to signal the first illuminating device and the secondilluminating device to illuminate the one or more target objects in asequential manner.
 13. The system for obtaining three-dimensionalinformation for one or more target objects as defined in claim 11,wherein the video microcontroller and the camera device are linked toenable the camera device to capture the images of the one or more targetobjects sequentially, while illuminated by the first and secondilluminating devices in sequence.
 14. The system for obtainingthree-dimensional information of one or more target objects as definedin claim 5, wherein the system is adapted to calculate distance byreplacing the two illuminating devices with two sound transducers. 15.The system for obtaining three-dimensional information of one or moretarget objects as defined in claim 5, wherein the system is integratedwith an automobile distance mapping system or accident preventionsystem.
 16. The system for obtaining three-dimensional information ofone or more target objects as defined in claim 5, wherein the system isintegrated with a robot to provide distance mapping information to therobot in relation to one or more target objects.
 17. The system forobtaining three-dimensional information of one or more target objects asdefined in claim 5, wherein the system is integrated with a trafficsurveillance system and is operable to obtain three-dimensionalinformation associated with automobiles, such three-dimensionalinformation providing a basis for establishing make and modelinformation for automobiles.
 18. The system for obtainingthree-dimensional information of one or more target objects as definedin claim 5, wherein the system is integrated with a distance mappingsystem that is operable to provide distance information relative to oneor more target objects to an individual with a visual impairmentregarding their physical environment.
 19. The system for obtainingthree-dimensional information of one or more target objects as definedin claim 5, wherein the system is integrated with a television studiosystem to provide three-dimensional information that enables editing ofone or more target objects in a three-dimensional studio environment.20. The system for obtaining three-dimensional information of one ormore target objects as defined in claim 5, wherein the system isintegrated with a biometric authentication system to enablebio-authentication of individuals based on touch-less capture ofbio-authentication information, including fingerprints.
 21. The systemfor obtaining three-dimensional information of one or more targetobjects as defined in claim 5, wherein the system is moveable to anarbitrary location.